Method and apparatus for reducing intraocular pressure of an eye

ABSTRACT

A method and shunt device for treating glaucoma includes positioning a first end portion of a tube body into the retrobulbar space of an eye. The method also includes positioning a second end portion of the tube body into the anterior chamber of the eye. The tube body provides fluid passage for aqueous humor such that the aqueous humor flows from the first end portion into the retrobulbar space. A surgical kit for reducing the intraocular pressure in the eye includes the shunt device, an introducer, and a stylet. The introducer has a distal end for positioning in the retrobulbar space and a proximal end for positioning exterior of the eye. The introducer has a radius of curvature adapted to circumvent the eye for insertion into the retrobulbar space.

TECHNICAL FIELD

The present invention relates generally to a method and apparatus forreducing intraocular pressure of an eye and, more particularly, totreating glaucoma.

BACKGROUND

Aqueous humor is naturally produced within the posterior chamber of theeye and serves a beneficial role to the health and function of the eyeitself. Most notably, the aqueous humor provides nutrition, such asamino acids and glucose, to various ocular tissues while simultaneouslypressurizing the eye and maintaining the correct intraocular structure.For this reason, aqueous humor is continuously produced and drained froma healthy eye to provide these important nutrients and maintain properintraocular pressure.

Normal intraocular pressure is generally between 10 mmHg and 20 mmHg. Inorder to maintain this pressure, aqueous humor inflows from theposterior chamber of the eye into the anterior chamber of the eye.Aqueous humor circulates throughout the anterior chamber where itnourishes the cornea, before exiting through the trabecular meshwork andinto Schlemm's canal. From there, it flows into the surroundinglymphatic channels. Under normal, healthy conditions, this cycle ofinflowing and outflowing aqueous humor continues unabated. However, insome instances, the drainage of the aqueous humor begins to slow due toan obstruction in the outflow from the eye. Because the inflow remainsthe same while the outflow decreases, intraocular pressure within theeye begins to increase over time. Generally, intraocular pressures over20 mmHg are considered a higher risk for damaging the optic nerve, andmay result in glaucomatous optic nerve loss. The effects of glaucoma areirreversible and, if left untreated, may lead to partial or completeblindness. In the United States alone, more than 120,000 people havebeen diagnosed as clinically blind as a direct result of thedebilitating effects of glaucoma. In fact, about 10% of all blindness inthe United States is caused by glaucoma. In the event glaucoma isdetected in a patient, it is important to quickly and effectively reduceintraocular pressure within the eye in order to prevent further damageto the optic nerve and preserve the patient's remaining vision.

Various treatments for glaucoma have been developed, but with mixedresults. Initially, glaucoma may be treated with medication in the formof eyedrops or pills to either decrease the inflow or increase theoutflow of aqueous humor. If this treatment fails, surgery may benecessary to reduce intraocular pressure. This can involve laserprocedures which treat the trabecular meshwork resulting in increasedoutflow, or treat the production site of aqueous humor, the ciliarybody, resulting in reduced inflow. Other surgical procedures fortreating glaucoma generally involve creating a drainage system withinthe eye for directing aqueous humor from the anterior chamber to anotherlocation within or around the eye to be reabsorbed by the lymphaticsystem. Frequently, a surgeon directs the aqueous humor to a bleb formedwith the conjunctiva tissue under the conjunctiva itself. This fluidconnection to the bleb creates a sealed system in which the aqueoushumor travels. Unfortunately, the healing characteristics of the eyework against the formation and maintenance of the bleb. As such, blebsare prone to scar down to the conjunctiva and/or become encapsulated,effectively blocking the outflow of the aqueous humor and, once again,increasing intraocular pressure.

In order to reduce the likelihood of bleb failure, plates may be placedon top of the sclera and sewn against the sclera in order to createadditional space to maintain the bleb. Generally, the additional spacecreates a larger bleb, thus reducing the likelihood of the bleb scaringdown. While this has proven mildly successful, the system must be sewnabsolutely watertight or the bleb will still leak, scar down, and fail.Such watertight seals are often times difficult to form and extremelytime consuming to create. Similarly, the fluid connection to theanterior chamber also is at risk for scaring closed or completelyplugging with adjacent iris tissue. To some extent, valve implants mayalso be used to maintain these fluid connections and facilitate theoutflow of aqueous humor. Unfortunately, for many patients, these toocan become surrounded by tough fibrous inflammatory tissues, calledencapsulation, rendering the entire procedure ineffective.

Moreover, these leaks, bleb failures, and fluid connections aredifficult to detect in the time immediately following the surgery. Forthis reason, repeated follow-up visits to the surgeon are required.Should the bleb fail over time, the patient has few, if any options torepair the bleb. Typically, the patient must undergo another timeconsuming, complex, tedious surgery hoping to create a new bleb prone tothe same, inherent risks of failure.

There is a need for a method and device for reducing intraocularpressure, particularly in the treatment of glaucoma, that addressespresent challenges and characteristics such as those discussed above.

SUMMARY

In one embodiment of the invention, a method of reducing intraocularpressure of an eye with a shunt device includes positioning a first endportion of a tube body into a retrobulbar space of an eye. The methodalso comprises positioning a second end portion of the tube body into ananterior chamber of the eye. Thereby, the tube body provides fluidpassage for aqueous humor from the anterior chamber of the eye to theretrobulbar space, whereby the aqueous humor flows from the first endportion into the retrobulbar space.

In one aspect, the method also includes maintaining a space between thefirst end portion and a retro-orbital tissue with a stent basket. Thestent basket is coupled to the first end portion so that aqueous humorpasses through the stent basket and into the retrobulbar space. Inanother aspect, implanting the shunt device positions a portion of thetube body between a sclera and a conjunctiva of the eye.

In another embodiment of the invention, a shunt device for reducingintraocular pressure within the anterior chamber of an eye comprises atube body and a stent basket. The tube body has a first end portion anda second end portion and is flexible with a lumen extendingtherethrough. The first end portion has an outlet adapted for beingpositioned within a retrobulbar space of the eye. The second end portionhas an inlet adapted for being positioned within the anterior chamber ofthe eye. The stent basket is coupled to the first end portion of thetube body and is in fluid communication with the outlet. Furthermore,the tube body is configured to allow pressurized aqueous humor to flowfrom within the anterior chamber to the retrobulbar space.

In one aspect, the shunt device also has a stent basket with a firststent end and a second stent end. The first stent end is closed, and thesecond stent end is coupled to the first end portion of the tube. Inaddition, the first and second stent ends are tapered for improving theinsertion and removal of the stent basket from an introducer insertedinto the eye.

In yet another embodiment of the invention, a surgical kit for reducingintraocular pressure within the anterior chamber of an eye comprises ashunt device, an introducer, and a stylet. The shunt device is flexibleand includes a tube body having a first end portion, a second endportion, and a lumen therethrough. The introducer has a distal end and aproximal end and is generally rigid with a cavity extendingtherethrough. The cavity is sized to receive the tube body. Furthermore,the introducer has a length and a radius of curvature configured tocircumvent the eye for accessing the retrobulbar space with the distalend. The introducer is also adapted to be removed proximally from thetube body such that only the first end portion of the tube body remainsin the retrobulbar space. The stylet has a handle and a piercing end.The stylet is sized to insert into the proximal end of the introducersuch that the piercing end extends distally from the distal end of theintroducer. The piercing end is configured to pierce tissue surroundingthe eye for positioning the distal end of the introducer in theretrobulbar space.

In one aspect, the introducer has an outer diameter, an inner diameter,and a radius of curvature. The outer diameter is from about 2millimeters to about 3 millimeters, the inner diameter is from about 1.5millimeters to about 2.5 millimeters, and the radius of curvature isfrom about 3 inches to about 4 inches.

Various additional objectives, advantages, and features of the inventionwill be appreciated from a review of the following detailed descriptionof the illustrative embodiments taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the invention and,together with a general description of the invention given above, andthe detailed description given below, serve to explain the invention.

FIG. 1 is a cross-sectional view of an eye having a shunt device fortreating glaucoma implanted therein.

FIG. 2A is a perspective view of the eye of FIG. 1.

FIG. 2B is a cross-sectional view of a globe of the eye of FIG. 1 havingan introducer inserted within the eye.

FIG. 2C is the cross-sectional view of the eye of FIG. 2B and the shuntdevice being inserted into the eye.

FIG. 2D is the cross-sectional view of the eye of FIG. 2C and a sleeveof the shunt device being removed from the eye.

FIG. 2E is the cross-sectional view of the eye of FIG. 2D and theintroducer being removed from the eye.

FIG. 2F is the cross-sectional view of the eye of FIG. 2E and the shuntdevice being positioned within the eye.

FIG. 2G is the cross-sectional view of the eye of FIG. 2F and the shuntdevice implanted within the eye.

DETAILED DESCRIPTION

With reference to FIG. 1, an embodiment of a shunt device 10 forreducing intraocular pressure is shown as implanted within an eye 12.The shunt device 10 generally comprises a tube body 14 having a firstend portion 16 and a second end portion 18. The shunt device 10 isimplanted within the eye 12 during a surgical procedure described belowin additional detail. With reference to directions relative to the eye12 shown in FIG. 1, an exterior 20 is proximal to the eye 12 while aretrobulbar space 22 is distal of the eye 12. The surgical procedure isperformed by a surgeon, such as a trained ophthalmologist or similarlyqualified professional, in order to fluidly connect an anterior chamber24 of the eye 12 to the retrobulbar space 22.

Accordingly, the tube body 14 is adapted to provide fluid passage foraqueous humor from the anterior chamber 24 to the retrobulbar space 22for reducing elevated intraocular pressure to normal, or otherwisehealthy, intraocular pressure. For instance, aqueous humor flows fromthe anterior chamber 24 to the retrobulbar space 22 with a flow ratesufficient to maintain intraocular pressure generally between 10 mmHgand 20 mmHg. With respect to FIG. 1, an inflow of the aqueous humor fromthe anterior chamber 24 is indicated by arrows 26, and an outflow of theaqueous humor into the retrobulbar space 22 is indicated by arrows 28.The retrobulbar space 22 includes retro-orbital tissue 30 known toabsorb approximately 5 cc to 6 cc of an anesthetic, such as lidocaine orMARCAINE®, used in retrobulbar blocks. In this same way, the retrobulbarspace 22 will be used to absorb aqueous humor, effectively draining theanterior chamber 24 of excess aqueous humor for reducing the intraocularpressure therein.

The schematic cross-section of the eye 12 will further aid in theunderstanding of the invention described herein. Generally, the eye 12is positioned within an eye socket 32. An upper eyelid 34 and a lowereyelid 36 are proximally positioned in the eye 12 and adjacent to theexterior 20. From a globe 37 of the eye 12, four primary extraocularmuscles extend distally to the bony apex of the orbit, providing ageneral boundary for a cone-shaped retrobulbar space 22, which itself isdistally positioned within the eye 12, behind the globe 37 and withinthe extraocular muscles. More particularly, a superior rectusextraocular muscle 38 extends along the top of the globe 37 and transitsthe retrobulbar space 22, while an inferior rectus extraocular muscle 40extends along the bottom of the eye 12 and transits the retrobulbarspace. Similarly, the retrobulbar space 22 is transmitted centrally byan optic nerve 42 extending rearwardly from the globe 37. First, asuperotemporal quadrant 44 of the retrobulbar space 22 is generallysuperior and lateral to the optic nerve 42, and below and lateral to thesuperior rectus muscle 38. Second, an inferotemporal quadrant 46 of theretrobulbar space 22 is generally inferior and lateral to the opticnerve 42, and superior and lateral to the inferior rectus muscle 40.Both the superotemperal quadrant 44 and the inferotemporal quadrant 46of the retrobulbar space 22 generally comprise a lateral space ofretro-orbital tissue 30 that, due to its high fat content, highvascularity, and high lymphatics content, is extremely absorptive of anyfluids that transudate from existing vessels or lymphatics, or of anyfluids placed into the retrobulbar space.

A central portion of the eye 12 is a vitreous cavity 46 positionedproximal of the optic nerve 42. A crystalline lens 48 is positionedproximal of the vitreous cavity 46 and supported by surroundingsuspensory ligaments 50, i.e., zonules, connected to a ciliary body 51which is responsible for the aqueous production within the eye 12. Theciliary body 51 is contiguous with the highly vascular choroid layer 52,which supplies oxygenation and nourishment to the outer layer of aretina 54 and forms an innermost layer of the eye 12 and serves toconvert light into electrical signals that may be transferred along theoptic nerve 42.

Furthermore, an annular iris 56 is positioned proximal of the lens 48.Generally, the iris 56 functions to modulate the amount of lightentering the eye 12. However, the iris 56 also splits a proximal portionof the eye 12 into two chambers. A posterior chamber 58 is positionedbetween the iris 56 and the lens 48. Aqueous humor is formed within theposterior chamber 58 by the ciliary body 51 and inflows around the innermargin of the iris 56 and into the anterior chamber 24 that ispositioned directly proximal from the iris 56. The anterior chamber 24is proximally bounded by a domed, clear cornea 60. In this way, theanterior chamber 24 is generally defined by the space between the cornea60 and the iris 56, while the posterior chamber 58 is generally definedby the space between the iris 56 and the lens 48.

In the event that the eye 12 is healthy, the aqueous humor flows out ofthe anterior chamber 24 through a ring of fenestrated tissue located atthe junction of the base of the cornea and the root of the iris known asa trabecular meshwork 61. The aqueous humor then enters a collectingchannel known as the Canal of Schlemm 62. The canal of Schlemm 62 ispositioned in a ring, inwardly adjacent to an annular junction known asa limbus 64 and just external to the trabecular meshwork 61. The limbus64, generally, is a junction of a generally spheroidal sclera 66 and thedomed cornea 60. The sclera 66 generally serves to support and shape theeye 12 and acts as an outer layer, relative to the choroid 52, thatprotects the inner structures of the eye 12 discussed above. Furtherprotection is provided to the eye 12 by a conjunctiva 68. Theconjunctiva 68 is a thin membrane covering the proximal portion of theeye 12 and extends from the limbus 64, covers the sclera 66, and thenreturns back along the inside of the upper and lower eyelids 34, 36.Finally, collecting channels (not shown) from the canal of Schlemm 62generally extend into the sclera 66 and connect with the lymphatics (notshown) of the globe 37. In this way, the aqueous humor may draindistally from the anterior chamber 24, into the lymphatic system (notshown), and enter into the blood stream (not shown).

The method of implanting the shunt device 10 in the eye 12 begins as aperitomy procedure in order to facilitate eventual access to theanterior chamber 24 and sclera 66. FIG. 2A shows the globe 37 of the eye12. An incision is made through the conjunctiva 68 adjacent to thelimbus 64 and the cornea 60 with scissors (not shown). Accordingly, theconjunctiva 68 is resected and pulled back, as shown in FIG. 2A, inorder to expose the sclera 66. Another incision is made at the exposedsclera 66 with a guarded step-knife (not shown) in order to make amid-thickness sclera incision. Furthermore, a crescent blade (not shown)is used to dissect into the mid-thickness sclera incision and extendedproximally to create a mid-thickness scleral flap 72 until the scleraflap 72 effectively folds proximally from the globe 37, and exposes theresidual scleral bed 74 below, and the gray-line (not shown) at theproximal extent of the incision. The gray-line is the anatomic landmarkfor the point of eventual entry into the anterior chamber 24 through thetrabecular meshwork 61. With respect to FIG. 2B, the sclera flap 72 issized and drawn proximal from the globe 37 far enough to provide accessthrough the gray-line (not shown) and into the anterior chamber 24positioned proximal to the gray-line. The sclera flap 72 is then laiddown against the residual scleral bed 74, while the remaining surgicalsteps are performed.

In order to access the retrobulbar space 22, the surgeon uses a surgicalkit that includes a stylet 78 in conjunction with an arcuate introducer80 and the shunt device 10 (see FIG. 1). The stylet 78 comprises anprojecting member 82 coupled to a handle 84. The projecting member 82 isgenerally flexible and includes a sharp, piercing end 85 distal of thehandle 84. The introducer 80 comprises a distal end 86, a proximal end88, and a cavity 90 that extends therethough. The introducer 80 isgenerally rigid and shaped to extend from the exterior 20 of the eye 12to the retrobulbar space 22. In addition, the introducer 80 isconfigured to circumvent the globe 37 while extending from the exterior20 to the retrobulbar space 22. More particularly, the introducer 80 hasa length and radius of curvature adapted to circumvent the globe 37 andextend into the retrobulbar space 22. For example, the introducer has aradius of curvature from about 3 inches to about 4 inches and a lengthof at least 1.25 inches or from about 1.25 inches to about 1.5 inches.More particularly, the introducer 80 has a radius of curvature of about3 inches, a length of about 1.5 inches, and an outer diameter from about2 millimeters to about 3 millimeters.

The distal end 86 is pointed for easing insertion of the introducer 80into the retrobulbar space 22. In addition, the proximal end 88 of theintroducer 80 is in the form of a funnel portion 95 that tapers distallytoward the cavity 90 therein. The proximal end 88 receives theprojecting member 82, which is configured to slide into the cavity 90 ofthe introducer 80. The projecting member 82 is also of sufficient lengthsuch that the piercing end 85 extends distally from the distal end 86while the handle 84 extends proximally from the introducer 80. Thereby,the surgeon may grip and manipulate the movement of the introducer 80and stylet 78 simultaneously at the interface of the handle 84 andfunnel portion 95, while inserting the introducer 80 into the eye 12with the piercing end 85 extending therefrom.

The piercing end 85 pierces tissue surrounding the eye 12 in order toposition the distal end 86 of the introducer 80 in the retrobulbar space22. More particularly, the piercing end 85 and introducer 80 areinserted above the eye 12 in order to position the introducer 80 withinthe cone of the extraocular muscles extending distally from the globe 37and, more specifically, within in the superotemporal quadrant 44 of theretrobulbar space 22. However, it will be appreciated that otherquadrants of the retrobulbar space 22, such as the infertemporalquadrant 46, may also be used in the procedure as described herein. Ofcourse, in the event of accessing another quadrant of the retrobulbarspace 22, the peritomy described above will need to be positionedelsewhere respective to the chosen quadrant. In any case, the introducer80 is inserted into the eye 12 between the conjunctiva 68 and the sclera66 and forced distally around the eye 12 in an arcuate path against thesclera 66. The distal end 86 continues distally into the superotemporalquadrant 44 of the retrobulbar space 22 until positioned about 0.25inches distal of the globe 37. Once the introducer 80 is positioned assuch, the stylet 78 is withdrawn from the introducer 80; thereby, givingthe surgeon access the retrobulbar space 22 for implanting the shuntdevice 10 shown in FIG. 2C.

With respect to FIG. 2C, a sleeve 96 is slidably positioned over thetube body 14 to aid in sliding the tube body 14 along the cavity 90within the introducer 80. The cavity 90 has an inner diameter adapted toreceive the tube body 14. More particularly, the inner diameter of thecavity 90 is from about 1.5 to about 2.5 millimeters. The sleeve 96 issemi-rigid and supports the tube body 14 to prevent the tube body 14from damage, such as deformation, that may occur while implanting theshunt device 10. More particularly, the sleeve 96 has an inner diameterfrom about 0.6 millimeters to about 0.8 millimeters and an externaldiameter from about 1.1 millimeters to about 1.4 millimeters. Moreparticularly, the inner diameter is about 0.7 millimeters, and theexternal diameter is about 1.25 millimeters. The tube body 14 is asilicon transfer tubing manufactured from flexible medical grade siliconconfigured to be implanted in the body. The tube body 14 defines a lumen98. The lumen 98 has an outlet 100 at the first end portion 16. Thelumen 98 has a diameter from about 0.2 millimeters to about 0.4millimeters, and the tube body has an outer diameter from about 0.55millimeters to about 0.75 millimeters with a length of about 4 inches.More particularly, the lumen 98 has a diameter of about 0.3 millimeters,and the tube body has an outer diameter of about 0.65 millimeters. Theflow rate of aqueous humor through lumen 98 may be chosen by selectingthe diameter of the lumen 98 that produces a desired flow rate. Inaddition, a medical grade stent basket 102 is coupled to the first endportion 16 and, as shown, is formed onto the first end portion 16 of thetube body 14. The stent basket 102 is in the form of a mesh structure104 with an internal void space defined by the mesh structure 104. Moreparticularly, the stent basket 102 is from about 5 millimeters to about8 millimeters in length, depending on the amount of pressure reductionneeded. More particularly, the stent basket 102 is generally from about2 millimeters to about 3 millimeters in diameter. The mesh structure 104is collapsible when forced into the funnel portion 95 of the introducer80 and re-opens when exiting the distal end 86 of the introducer 80.According to the exemplary embodiment, the void space of the stentbasket 102 is about 0.02 cubic centimeters. As such, the stent basket102 is adapted to allow aqueous humor to pass through the void spacewhile the mesh structure 104 maintains a space between the outlet 100and the retro-orbital tissue 30.

With respect to FIGS. 2C and 2D, the surgeon inserts the tube body 14and the stent basket 102 into the introducer 80, as indicated by arrow106. More particularly, the first end portion 16 is positioned generally0.25 inches behind the globe 37, as described above. In order to insertthe stent basket 102, the mesh structure 104 is collapsible from anexpanded configuration to a contracted configuration when sufficientforce is applied to the mesh structure 104. This force is applied whenthe stent basket 102 is forced within the cavity 90. However, in orderto aid in collapsing the mesh structure 104, a first stent end 108 and asecond stent end 110 are tapered. The second stent end 110 is formedonto the first end portion 16 of the tube body 14 open to the outlet100. In contrast, the first stent end 108 is formed of the meshstructure 104 and relatively closed, except for the void space withinthe mesh structure. The tapered first and second stent ends 108, 110help to funnel and contract the mesh structure 104 as the mesh structure104 moves in and/or out of the tube body 14. In this way, the stentbasket 102 may be implanted or removed from the retrobulbar space 22 byway of the tube body 14 used in conjunction with the introducer, withoutdamaging the eye 12. According to the exemplary embodiment, the stentbasket 102 has an expanded diameter from about 2 millimeters to about 3millimeters in the expanded configuration and a contracted diameter offrom about 1.5 millimeters to about 2.5 millimeters in the contractedconfiguration. While the exemplary embodiment shows the stent basket102, it will be appreciated that the invention described herein is notintended to be limited as such. More particularly, the stent basket 102may also be deployed from the contracted configuration to the expandedconfiguration using any device and/or method known to one of ordinaryskill. For example, the stent basket 102 may be deployed using anadditional expansion device (not shown), such as a dilation balloon. Onesuch a device and method is described in U.S. Pat. No. 6,019,777, thedisclosure of which is hereby incorporated by reference herein. In thealternative, the shunt device 10 may not include a stent basket 102.

Once the first end portion 16 is implanted or otherwise positionedwithin the retrobulbar space 22, the tube body 14 is held relativelystationary while the sleeve 96 is withdrawn from the introducer 80, asindicated by arrow 112 in FIG. 2D. Similarly, as shown in FIG. 2E, theintroducer 80 is withdrawn from the retrobulbar space 22 along the samepath with which it was inserted into the eye 12 as indicated by arrow114. Thus, all that remains within the eye 12 is some portion of thetube body 14 positioned between the sclera 66 and conjunctiva 68 and thefirst end portion 16 in the retrobulbar space 22 shown in FIG. 2F.

As mentioned briefly above, the tube body 14 is at least about 4 incheslong in order to provide ample length with which to manipulate the tubebody 14. However, FIG. 2F shows that the tube body 14 is cut, such as abevel cut, to form the second end portion 18 of the tube body 14.Thereby, the lumen 98 has an inlet 116 at the second end portion 18.After forming the second end portion 18, the length of the shunt device10 from the first end portion 16 to the second end portion 18 is about1.25 inches. However, it will be appreciated that the length may beadapted to accommodate the distance from the retrobulbar space 22 to theanterior chamber 24 that may be relatively unique to each patient.

A needle (not shown), such as a 27 gauge needle, is inserted through thegray line portion 74 and into the anterior chamber 24 in order to forman access hole 118 therethrough. Once the access hole 118 is formed, thesecond end portion 18 is inserted through the access hole 118 and intothe anterior chamber 24 as indicated by arrow 120. More particularly,the second end portion 18 is inserted into the anterior chamber 24 fromabout 2 millimeters to about 4 millimeters. In addition, the tube body14 is attached to the globe 37 and the sclera flap 72 is sewn back tothe sclera 66 as shown in FIGS. 2F and 2G. More particularly, aplurality of sutures 122 a, 122 b, 122 c are positioned around the tubebody 14 and through the sclera 66 to attach the shunt device 10 to theglobe 37. The sclera flap 72 is laid over the access hole 118 and thetube body 14, as indicated by arrow 121. At least one suture 122 a ispositioned through the sclera flap 72 and the sclera 66 in order toensure proper healing of the sclera 66 at this incision location.However, two of the sutures 122 a may also be used to sew down thesclera flap 72 if necessary. Additional sutures 122 b, 122 c may also bepositioned through the sclera 66 distal of the sclera flap 72. On onehand, these additional sutures 122 b, 122 c help maintain the positionof the tube body 14. On the other hand, the additional sutures 122 b,122 c are tightened over the tube body 14 to constrict the lumen 98therein. Accordingly, flow of aqueous humor from the inlet 116 to theoutlet 100 may be restricted to selectively limit the flow of theaqueous humor from the anterior chamber 24. According to the exemplaryembodiment, the plurality of sutures 122 a, 122 b, 122 c are formed fromnylon and placed about 1 centimeter apart. The sutures 122 a, 122 b, 122c, as shown in the exemplary embodiment, are 10-0 interrupted sutures;however, it will be appreciated that a long mattress suture (not shown)may also be used. In any case, with the first and second end portions16, 18 appropriately positioned as described above and the tube body 14sutured to the sclera 66, the shunt device 10 is now implanted withinthe eye 12 for fluidly communicating aqueous humor from the anteriorchamber 24 to the retrobulbar space 22 as shown in FIG. 2G.

After approximately four to six weeks, the patient should return to thesurgeon for a follow-up appointment to ensure that the shunt device 10is functioning as intended. In the event that the surgeon chooses toincrease the flow rate of the aqueous humor to the retrobulbar space 22,the surgeon may selectively tighten or release one or more of thesutures 122 a, 122 b, 122 c in order to respectively decrease orincrease the diameter of the lumen 98. Thereby, the flow rate of theaqueous humor may be selectively decreased or increased by restrictingor expanding the tube body 14. However, once the flow rate of theaqueous humor is selected by the surgeon and the shunt device 10 isfunctioning properly, the patient does not need to return for follow-upappointments related specifically to the implanted shunt device 10. Onone hand, previous glaucoma treatments using blebs require regularfollow-up appointments, because the risk of the bleb to scaring down iscontinuous. On the other hand, the shunt device 10, described above,works in conjunction with the natural ability of the eye 12 to heal andscar down. Moreover, there is no need for a watertight conjunctivalclosure since the aqueous humor is being directed into the retrobulbarspace 22, which is relatively naturally-sealed. In this way, theimplantation of the shunt device 10 is considerably simpler and lesstime consuming than previous treatments.

In the event that the shunt device 10 requires removal from thepatient's eye 12, the above treatment need only be practiced generallyin reverse. More particularly, the plurality of sutures 122 a, 122 b,and 122 c should be released and the second end portion 18 should beremoved from the anterior chamber 24. The introducer 80 is slid over thetube body 14 and inserted into the eye 12 along the same path describedabove. With the introducer 80 once again positioned in the retrobulbarspace 22, the tube body 14 is withdrawn through the introducer 80.Accordingly, the tapered second stent end 110 forced against theintroducer 80 contracts the stent basket 102 and the entire shunt device10 may be removed from the eye 12. Finally, the introducer 80 issimilarly withdrawn from the eye 12 to complete the reversal of themethod.

While the present invention has been illustrated by the description ofone or more embodiments thereof, and while the embodiments have beendescribed in considerable detail, they are not intended to restrict orin any way limit the scope of the appended claims to such detail.Additional advantages and modifications will readily appear to thoseskilled in the art. The invention in its broader aspects is thereforenot limited to the specific details, representative apparatus and methodand illustrative examples shown and described. Accordingly, departuresmay be from such details without departing from the scope or spirit ofthe general inventive concept.

What is claimed is:
 1. A method of delivering a portion of a shuntdevice to the retrobulbar space to reduce intraocular pressure of an eyewith the shunt device, comprising: positioning a first end portion of atube body of the shunt device into a retrobulbar space by inserting anarcuate introducer and stylet into the eye adjacent to the sclera andextending the arcuate introducer and stylet into the retrobulbar space,withdrawing the stylet from the arcuate introducer, guiding the tubebody with a sleeve through the arcuate introducer until a first endportion of the tube body is inserted into the retrobulbar space, whereinthe sleeve is positioned over the tube body and aids the tube body insliding within the arcuate introducer, withdrawing the sleeve from thearcuate introducer and tube body, and withdrawing the arcuate introducerfrom the retrobulbar space leaving the first end portion of the tubebody implanted in the retrobulbar space; positioning a second endportion of the tube body into an anterior chamber of the eye byinserting the second end portion of the tube body through the sclera andinto the anterior chamber thereby fluidly connecting the anteriorchamber to the retrobulbar space, thereby providing fluid passage foraqueous humor from the anterior chamber of the eye to the retrobulbarspace; maintaining a space between the first end portion and aretro-orbital tissue with a stent basket coupled to the first endportion, wherein the aqueous humor passes through the stent basket intothe retrobulbar space; and draining aqueous humor from an anteriorchamber of the eye to a retrobulbar space through the shunt device. 2.The method of claim 1 further comprising expanding the stent basketwithin the retrobulbar space.
 3. The method of claim 1 furthercomprising positioning a portion of the tube body against the sclera ofthe eye.
 4. The method of claim 3 further comprising positioning theportion of the tube body between the sclera and the conjunctiva of theeye.
 5. The method of claim 1 further comprising attaching the tube bodyto the sclera with a suture around the tube body, wherein the suture ispositioned distal of a sclera flap, and adjusting the flow rate of theaqueous humor through the tube body by tightening or releasing thesuture from around the tube body.